Steve, if your going in at cat 4, I wouldn't get to caught up in the rules, Rim Depth will be a dead give away but spoke count and bike weight arn't going to be noticed, that sort of stuff is when you hit cat 2 and above, and even then you would be unlucky to have been caught. No one gets stuck at a weighing scale or a calculator at many races these days
I'm aware of rim depths/area for TTing, but what are they for racing? T-Mobile had rather deep wheels at the Tour, but for BChave they set a national limit?
I suppose Cosmic Carbones are fine at 55mm, and no doubt HED Jet 60s are ok, but are you pushing it after that?
I'm sure as long as you use your own initiative you should be ok. if you go to your first race with deep rim's and a carbon fibre stead looking for the win only to be blowing out your arse into the 10th lap your going to look a little bit of a plum. go with what you got, attend a race to see what some of the other lads and ladies are using and go from there.